In the automotive sector, metal parts are increasingly being replaced by polymeric materials for the purpose of, for example, reducing the car's weight and preventing corrosion. High requirements are however imposed on polymeric materials used in car parts. The polymeric materials must have excellent mechanical properties, for example high stiffness, fatigue resistance, tenacity and impact resistance and little creep. The materials must have a high heat deflection temperature. A high oxidative stability and chemical resistance to, for example oils and greases, are also requirements that the material employed must meet. Limited moisture absorption is important with respect to obtaining a high dimensional stability of the car part. Depending on the place in which the car part will ultimately be used, the polymer composition will have to exhibit some of the properties mentioned above to a greater extent than others and/or will have to possess additional properties. If the part is to be used in for example the bodywork (bumpers, wings, wheel housings, door panels, spoilers, etc.) a combination of sufficient stiffness and impact resistance and an excellent surface quality of the polymer composition will require special attention. The heat deflection temperature is an extremely important factor for both parts of the bodywork and for parts under the bonnet. Parts of the bodywork are exposed to high temperatures, for example during painting at high temperatures. Parts under the bonnet are constantly exposed to the high heat of the engine. Examples of such parts are air inlet manifolds and radiator end caps. The heat deflection temperature (HDT) is the temperature at which a rod made of the material in question shows a prescribed deflection when it is subjected to a certain flexural stress under three-point loading. Usually, a material cannot be used at temperatures above its heat deflection temperature because the material loses its strength and stiffness at this temperature.
Conventional polyamide materials, such as nylon 4.6 and nylon 6.6, which find wide application in car parts, do not satisfy all the aforementioned properties that are many times required for use in car parts. A drawback of nylon 6.6, for example, is that its heat deflection temperature is not high enough for many applications in car parts under the motorhood. The aliphatic nylon 4.6 does not show this limitation. A drawback of polyamide 4.6, however, is that it absorbs a relatively large amount of moisture, as a result of which its dimensional stability is in many cases insufficient.